/Engine/Source/Runtime/CoreUObject/Public/Misc/PackageName.h
Attempts to find a package given its short name on disk (very slow).
true if the specified package name points to an existing package, false otherwise.
static bool SearchForPackageOnDisk ( const [FString](API\Runtime\Core\Containers\FString) & PackageName, [FString](API\Runtime\Core\Containers\FString) * OutLongPackageName, [FString](API\Runtime\Core\Containers\FString) * OutFilename )